How to create simple slopes

I was making stairs for my map. However, the hammer editor froze at PortalFlow when compiling the map. It was probably due to too many brushes when making the stairs. So I decided to make slopes instead of stairs to reduce the brushes and faces. I was googling but no one has the tutorial of making slopes, only stairs. How to make slopes? Not the kind of slope for surfing, just a simple slope.
:O

I just want to point out, that even though Hammer begins "Not Responding" it more than likely hasn't frozen. The compile is just taking too long to update the window with new information so Windows considers it frozen. Hammer will quite regularly stop responding even for my short <1 minute compiles, and in my 10+ years of mapping I think I've only had a compile actually freezecrash maybe 3 or 4 times.

To add to what ABS said, I always time the compiling with the stopwatch on my phone. Then I go do something else because "a watched pot never boils". This way if all my compile times have been about two minutes normally then I hit one that is taking five minutes or more, then I can safely assume it probably crashed.